Process of and apparatus for manu



R. WEINGAND Sept. 25, 1934,

Original Filed Jan. 9, 1929 PROCESS OF AND APPARATUS FOR MANUFACTURING SEAMLESS FLEXIBLE TUBES lNVENTOR ATTORNEYS Reissued Sept. 25, 1934 UNITED STATES PATENT" OFFICE PROCESS OF AND APPARATUS FOR MANU- FACTURING SEAMLE S S FLEXIBLE TUBES Richard Weingand, Bomlitz, near Walsrode, Germany, assignor to Sylvania Industrial Corporation, Fredericksburg, Va., a corporation of Virginia 10 Claims.

This invention relates to a process of and apparatus for manufacturing seamless flexible tubes from cellulose solutions, particularly viscose.

' It has already been proposed to make seamless flexible tubes from solutions of cellulose by forcing the originating solution, under considerable pressure, through a long passage formed between two coaxial cylinders, and to bathe the resulting layer with a precipitant liquid, inside and out simultaneously, on issuing from said passage, compressedair being admitted at the same time into the interior of the tube in order to preserve its tubular shape. The employment of compressed air and pressure. complicates this method of operation, and the requisite apparatus therefor, and easily leads to working troubles. Moreover, the admission of compressed air into the interior of the tube in course of formation, makes it very diflicult to obtain a uniform thickness of wall and a uniform diameter throughout the flexible tube, since in practice, the air pressure is not uniform, and the resulting tube is still very ductile. Attempts have therefore been made to produce seamless flexible tubes from cellulose solutions by immersing corresponding formers into the originating solution; but only comparatively short tubes can be obtained by this method.

The present invention contemplates the manufacture of seamless tubing of any desired length, by a novel method of operation and improved apparatus, and in a continuous manner, without the aid of positively applied pressure-or compressed air whereby a product is obtained possessing superior-properties of strength and elasticity and having a uniform wall thickness and a uniform diameter. Y

In the'accompanying drawing, Fig. Us a sectional view in side elevation of one embodiment of the novel apparatus of the invention; 1 a

. Fig.2 is asectional view in side elevation of another embodiment of the apparatus of the invention; and

Fig. 3 is a sectional view in side elevation of a further; embodiment of the apparatus of the invention; i

.In the apparatus of the invention there is provided an annular nozzle positioned to extrude a solution downwardly and a guide member positioned coaxial therewith and disposed beneath the nozzle so as to interiorly support a tube immediately upon extrusion from the nozzle. The guide member is'cylindrical in form and has a uniform diameter equal to that of the nozzle. There'is provided also a conduit for supplying the cellulose solutions to the nozzle, and a conduit for supplying a coagulant to the interior of the extruded tube and means for supplying a coagulant to the exterior of the tube at a distance from said nozzle.

In the practice ofthe invention, a suitable cellulose solution is extruded downwardly, preferably solely by gravity through an annular nozzle, the extruded tube being interiorly supported by passing it over a guide member. The interior of the extruded tube is coagulated without coagulating the exterior; thereafter the exterior of the tube is coagulated, the internal coagulant being supplied in an amount such that no excess thereof accumulates in the interiorof the, tube after the coagulation is complete. I j

Preferably, the flowing of the cellulose solution from the annular nozzle to the'precipitating bath takes place along a guide member bathed, with precipitant liquid inside the flexible tube to be formed. The cellulose solution is coagulated internally immediately on issuing from the nozzle and assuming the tubular form. The layer of precipitant which surrounds continuously and uniformly the guide member onits whole surface and length enables the formed tube of cellulose solution to slide along the guidemember' by gravity alone towards the precipitating bath. Thus, a shrinkage during this sliding movement is prevented by guiding the moving layer on a solid body during the coagulation The resulting tube detaches itself automatically from the lower end of the guide member and then,is coagulated exteriorly by a suitable coagulant. At least part of the guide member extends above the level of the liquid in the bath. The amount of the coagulant supplied to the guide. member for bathing the same, is preferably so adjusted that it will becom-' pletely consumed during the coagulation from the inside so that no excess of liquid accumulates in the interior of the tube during the formationof the tube. r

The accompanying drawing shows by way of example several embodimentsof apparatus suitable for carrying the process according to the invention into practical ,eifect. 4

In the embodiment of the invention illustrated in Fig. 1, thecellulose solution is fed intov a funnel 11 which merges into an annular nozzle 12, into the inner rim of which projects a guide member 13, which may, for example, be cylindrical. A tube 14 passingthrough the annular nozzle 12 serves for supplying a coagulating liquid to the guide member 13, and is provided with a control valve-15. Below the guide member 13 is a vessel 16v containing a coagulating bath. The cellulose the lower end of the guide memberlB and sinks,

into the bath in vessel 16 wherehthef r mm coagulation is efiected.

The solidified tube 1'7 can beremoved from the vessel 16 by means of rollers 19, and' can be treated in a continuousmanner i'rrthe usual regenerating, Washing, bleaching, des'ulphu' rizing,

colouring and plasticizing baths, followed, i1 de- H sired, by drying. By adjusting the control valve 15, the supply of coagulating medium to the guide 1 member 13, and thereby the rate of removal of thetubecanberegulated.

As illustrated in Fig. 2, the annular nozzle 12 01' Fig. lymay be replaced by'a cylindrical tube 20, into which is inserted the'slightly conical up'-' per end 21 of a guide member-13 disposedco'axial with the tube 20, so that the thickness and form ofthe tube in course of formation, is determined by the space between these two memberswhich may be adjustable. In order to ensure the'su'pply of coagulating medium to the guide member 13, the tube 14 serving to supply the same, may be provided at its lower end with 'a conical cover 22 .i-

Fig. 2 further shows that the external cagu: lation of the tube may also be e'fiectedwhile the tube is still on the guide member 13, inasmuch as this member may, for example, be partly ir'n mersed in the coagulating bathk In" the embodi- V ment of the apparatus shown in Fig. 3, theuse 40 of a vessel containing a. coagulating bath isfdis pensed with and the tube externally irrigated with precipitant by means 'of an annular nozzle 24 surrounding the tube and supplied with coagf ulant by a suitable inlet tube 25 provided with a valve 26. The spray nozzle 24 is'disposed'so that the spray of coagulant 8 strikes the tube 17 at'a distance below the tube-forming orifice 2'7, and the point of internal coagulation of the tube.

The ,tube resulting from the novel process'of the invention may serve for any desired purposes and may be employed'for example as an artificial sausage casing.

1. In an apparatus for the manufacture of seamless flexible tubes from cellulosesolutions, the combination of an annularnozzle positioned to extrude the solution downwardly, a guide mem'- her having a uniform diameter equal to that of the nozzle and disposed beneath and coaxial with said nozzle so as to interiorly support a tube im-j mediately upon extrusion from said nozzle, means for supplying cellulose solution .to' said: nozzle, means for supplying a coagulant to said guide member adjacent the nozzle, and means for sup- '3 plying a coagulant to the'exteriorl of theextruded tube at a distance from. saidnozzle; A

2. In an apparatus forthe manufacture of seamless flexible tubes from cellulose solutions, the combination of an" annjul'ar'nozzle positioned 3 to extrude the solution downwardly and comprising two concentric cylindrical 'members, a guide member having a uniforni'diameter'equal to that of the nozzle and disposed beneathan'd coaxial with said nozzle so as to interiorly'-sup-' port a tube immediately upon extrusion'i fro'm said nozzle, means for supplying cellulose solutionto saidr'iozzle', means for supplying a coagulan't to bathe said'guide member adjacent the nozzle, and a vessel containing a coagulating bath positioned beneath said nozzle, at least part of said guide member extending above the level of s the liquid in saidbath.

.3; an apparatus for the manufacture of disposed withinsaid cylindrical tube and forming with said tube an annular nozzle positioned to extrude the solution downwardly, said guide member having a uniform. diameter equal to that of thenozzle, mea'nsfor supplying cellulose solution to said tube, means for supplying a coagulant to bathe'said guide member adjacent the nozzle, and means for supplying a coagulant to the exterior of the extruded tube at a distance from said'nozzle. f

"4.1m an apparatus for" the manufacture of seamless flexible tubes from' cellulose solutions, the'co'mbiriation'of an annular nozzle positioned toextrude the solution downwardly, a guide member having-a uniform diameter equal'to that of the nozzle and disposed beneath and coaxial with said nozzle so 'as-to interiorly support a tube immediately' upon extrusion from said nozzle, means for supplying cellulose solution to said nozzle, meansfor supplyinga coagulant to bathe said guide member adjacent the nozzle, and a second annular nozzle surrounding the guide member and disposed to supply coagulant to the exterior of the extruded tube at a distance from'said nozzle Y 5. In a process 'for'the'manufacture of seamless'fie'xibletubin'g from cellulose solutions, the steps'=-whi'chcomprise extruding a suitable cellulose solution downwardly through an annular nozzlefinteriorly supporting the extruded tube, coagulating the interior of the tube without coagulating; the exterior of the tube, thereafter coagulating'the exterior of the tube.

6. In a process for the manufacture of scamless flexible tubing'fr'om viscose solutions, the steps which comprise -'extruding a' suitable viscose solution downwardly' throu'gh an annular nozzle, interiorly supporting the extruded tube, coagulating the interior of the extruded tube without coagulating the exterior of the tube, and thereafter coagulating the exterior of the tube, the internal coagulant being supplied in an amount such that no excess thereof accumulates in the interiorof the tube. I

7. In a process for the manufacture oi seamless flexible tubing from cellulose solutions, the steps" which comprise extruding a suitable cellulose solution downwardly through an annular nozzle, interiorly supporting the extruded tube; coagulating the interior of. the extruded tube immediately as it issues from saidnozzle without coagulating the exterior of the tube, and there aftercoagulating' the exterior or thetube.

8. a process 'for the manufacture oftseam, less flexible tubing from cellulose solutionathe steps-which comprise extruding a suitable cellulose solution downwardly through an annular nozzle; supporting the extruded tube by means of a guide 'member, bathing the guidemembe'r with-a coagulant 'ofthe solution, coagulating the interior of the-tube on the guide member without coagulating the exterior, and thereafter. coagulating the exterior of the tube after it has passed f-roin'said: guide-member.

Ill)

9. In a process for the manufacture of seamless fiexible tubing from cellulose solutions, the steps which comprise extruding a suitable cellulose solution downwardly through an annular nozzle, interiorly supporting the extruded tube by means or" a guide member, bathing the guide member with a coagulant of the solution, coagulating the interior of the tube on the guide member without coagulating the exterior, and thereafter coagulating the exterior of the tube, the rate of extrusion being controlled by varying the amount of coagulant supplied to bathe the guide member.

10. In a process for the manufacture of seamless flexible tubing from viscose solutions, the steps which comprise extruding a suitable viscose solution downwardly through an annular nozzle solely by the force of gravity, interiorly supporting the freshly extruded tube by means of a guide member, bathing the guide member with a coagulant of the solution, coagulating the interior of the tube on the guide member without coagulating the exterior, and. thereafter coagulating the exterior of the tube after it has passed from said guide member, the internal coagulant being supplied in an amount such that no excess thereof accumulates in the interior of the tube.

RICHARD WEINGAND. 

